This is a continuation of Project HL22110-02. The program is designed to define the pathophysiology and formulate methods of management for the two principal complications of vascular grafting, infection and thrombosis. The objective of the program is to reduce the incidence of these complications by identifying those aspects of graft design and material that are experimentally associated with a reduced susceptibility to bacteremic infection or thrombosis. Data from previous studies in our laboratory indicate that transient bacteremia is a potential mechanism for infection in prosthetic arterial grafts; that the incidence of infectability is reduced with healing time; and that the specific aspect of healing that provides protection against bacteremic infection is the development of a complete pseudointima. Pilot studies suggest that variability of the healing-time/infectability relationship exists between prosthetic grafts of difference design and material. A series of experiments are designed to definitively identify these differences and to identify the graft material and methods of fabrication that provide for the most rapid and complete healing as a means of reducing the vulnerability to bacteremic infection. The project is also designed to develop alternative materials for arterial reconstruction in the presence of infection or wound contamination. Data from previous studies in our laboratory indicate that fresh autogenous artery and vein as well as fresh allograft artery will heal and function when implanted in an infected wound. A series of experiments are planned to evaluate the use of cryopreservation as a method for providing convenient availability of fresh, live allograft materials for implantation in an infected or contaminated field. The development of this technology will also be applied to the final area of interest which is the establishment of techniques that will provide arterial grafting materials 4mm or less in diameter that will be readily available for implantation and have a low rate of thrombosis. A series of experiments in small vessel replacement is planned using cryopreserved allograft conduits. Methods of evaluation for these arterial segments will include comparisons of intimal surface thrombogenicity as well as longterm patency.